Kurokouchi Keita is the black sheep of the police force. He works alone, and doesn't think twice about extorting money from the dirty politicians by getting hold of their achilles heels. Using the money and whatever bits of information acquired through underhanded means, he gets closer and closer to the ultimate unresolved crime of the Showa era (1968); the 300 million bank heist.

One day, the new rookie Seike Mayo, is assigned as Kurokouchi's partner. Excellent, but naive, she is the exact opposite of Kurokouchi, but nonetheless, the duo relentlessly chase down the criminals.